The Northeast Collaborative Access Team (NE-CAT) is developing an Undulator Resource for Structural Biology at Sector 24 of the Advanced Photon Source (APS). The main focus of the resource is to optimize high brilliance undulator radiation for technically challenging crystallographic experiments. The NE-CAT sector design utilizes a novel insertion device configuration in which two canted undulators are placed in a single straight section. One undulator provides beam to a tunable end station (24-1D-C), and the second undulator provides beam to a monochromatic side station (24-1D-E). The Sector 24 bending magnet will provide beam to a soon-to-be-completed tunable station (24-BM). Each station is equipped with an ADSC Quantum 315 CCD detector, goniometers, sample cryrocoolers and remote crystal visualization cameras. Crystal automounters will be provided for all three stations. Beamline control is provided by ADSC, CONSOLE and EPICS with either CONSOLE or Blu-lce GUI's. We will develop three core technologies during the next grant period: (1) microdiffraction, (2) hardware for challenging samples and (3) computing for challenging samples. The goal of core 1 is to develop the first beamline in the US dedicated to microdiffraction of biological macromolecules. The goal of core 2 is to optimize beam stability, beam focus and signal-to-noise for challenging samples. The goal of core 3 is to develop flexible beamline control software, and to optimize data collection and processing strategies for non-standard cases. The core technologies will be driven by 11 collaborative science projects involving a wide variety of challenging crystals and a wide range of biological applications. The user program is now operational for beamline 24- ID-C. Beamline 24-ID-E will be operational in the summer of 2007, and 24-BM will be operational in about a year. General users will receive 50% of the available beamtime, and the remaining 50% will go to NE-CAT members. The Resource plans extensive training and dissemination programs including on-site user training, web-based tutorials and screencasts, and off site mini-symposia. We will organize annual workshops related to data collection and structure determination. The Resource will publish a biannual electronic newsletter as a tool to inform the scientific community about NE-CAT developments and as an aid in building our user base. We will continue to maintain an extensive web site, present papers at scientific meetings, publish technical developments and scientific results, and contribute to the APS design library.